Automobile Maintenance, Servicing and Troubleshooting
Automobile Maintenance, Servicing and Troubleshooting
This domain tests planned servicing and logical fault finding. Expect service schedules, fluid checks, filter replacement, brake and tyre inspection, and diagnosis from symptoms such as smoke colour, noise, vibration and overheating.
Core rules
- Preventive maintenance follows time or distance intervals: engine oil and filter, air filter, coolant, brake fluid, tyre rotation and brake inspection.
- Troubleshooting starts with the complaint, then checks the simplest and safest causes before replacing parts. Confirm the fault, locate the system, test the component, then repair and verify.
- Exhaust smoke: blue-grey indicates burning oil; white indicates coolant or condensation; black indicates a rich mixture.
- Overheating causes include low coolant, a stuck thermostat, a failed radiator fan, a slipping water-pump belt, a blocked radiator or a head-gasket leak.
Worked example
A car overheats in slow traffic but returns to normal on the open road. Reasoning: at low speed there is little ram-air through the radiator, so the electric cooling fan is critical; on the highway, airflow masks a failed fan. The likely fault is the fan circuit, not the thermostat. Check the fan fuse, relay, motor and temperature switch before replacing the radiator.
Traps
- Replacing parts before confirming the fault, wasting cost and masking the cause.
- Using the wrong oil grade or overfilling the sump.
- Ignoring a brake fluid leak because the pedal still feels firm.
- Treating black smoke as normal on a diesel; it can indicate over-fuelling or a restricted air filter.